We are all familiar with the North-South divide that prevented agreement on a new climate treaty at Copenhagen last year. Relying on the principles of "Common But Differentiated Responsibility," the developing countries led by China, Saudi Arabia, Brazil and South Africa refused to adopt any proposal that would require them to reduce carbon emissions.

Meanwhile, the developed countries, most significantly the U.S., adamantly opposed any deal that would leave out these countries’ large and growing contributions to the global climate problem.

Now, one can debate the appropriateness of labeling countries like China and Saudi Arabia as "developing" when China has the second largest economy in the world and Saudi Arabia represents significant oil wealth.

The distinction between developed and developing nations is even murkier in the context of international shipping. Ship owners can register their vessels in any country they choose under a "flag of convenience" and thus avail themselves of the laws and regulations most favorable to their industry, and often least favorable to worker safety, human health and the environment.

So how does this relate to the politics of carbon?

Well, last week I attended the most recent meeting of the International Maritime Organization (IMO). On the agenda was consideration of mechanisms to reduce carbon emissions from international shipping.

Shipping represents nearly three percent of global CO2 emissions and the Kyoto Protocol requires that the parties work through the IMO to reduce these emissions. However, the prospects for mandatory action through the IMO to reduce carbon emissions looks remote.

The reason? The developing countries’ adamant position that they not be required to reduce emissions on the basis of the common-but-differentiated-responsibility principle. But as I mentioned, this principle doesn’t fit squarely onto the world of international shipping.

Approximately 70 percent of the world’s shipping fleet are registered in developing countries, rendering ineffectual any attempts to regulate carbon emissions that only applies to ships registered in developing countries.

Moreover, because many ships registered in developing nations are actually owned by corporations based in developed countries, hiding behind the flags of developing nations unfairly grants developed-world corporations and citizens the protections of common-but-differentiated-responsibility.

Unfortunately, with the next round of international negotiations on the successor to the Kyoto Protocol fast approaching there was no room for such subtleties at the IMO. Positions are entrenched and progress on reducing carbon emissions from international shipping has been held hostage by the politics of carbon.